CVE-2026-43050
Description
A flaw was found in the Linux kernel's Asynchronous Transfer Mode (ATM) LAN Emulation Client (LEC) module. A race condition exists where the priv->lecd pointer can be set to NULL while other threads are still accessing it. This can lead to a use-after-free memory corruption vulnerability when the socket's wait queue is accessed, potentially causing system instability or a denial of service. The issue stems from insufficient synchronization during the clearing of the priv->lecd pointer.
Statement
LAN Emulation (LEC) ATM path could UAF in sock_def_readable() during async disconnect; upstream fixes reference lifetimes. Red Hat recommends patched kernels where lec is used; unload module if ATM LANE unused.
Mitigation
To mitigate this issue, prevent the lec module from being loaded. See https://access.redhat.com/solutions/41278 for instructions.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | 7 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | High | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | High | N/A |
| Integrity Impact | None | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
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